1. Field of the Invention
The present application concerns the use of iodine containing materials to disinfect protein-containing solutions such as blood, blood fractions, enzymes and vaccines
2. Description of Related Art
There is an almost daily discovery of some exotic new pathogen that is transmitted by blood transfusion or by intimate contact. Human immunodeficiency virus (HIV, the causative agent of AIDS) and the plethora of new hepatitis viruses leap to mind, but many other serious disease-causing agents that are communicated in similar ways are being discovered constantly. It seems that the human habit of cooking its prey has long shielded us from many viruses that require blood to blood transmission. Now modern medicine with its use of transfusions and blood and tissue fractions has removed that shield. Many workers have been experimenting with a variety of disinfecting chemical and physical agents to try to eliminate virus and other disease-causing agents from blood and other medical materials.
The present inventor has disclosed a considerable number of inventions based around the use of free elemental iodine to kill or inactivate a large range of microbes (bacteria, virus and other pathogens) particularly in protein-containing solutions such as human blood, human plasma or fractions thereof. The reader's attention is drawn to U.S. Pat. Nos. 5,019,495; 5,128,149; 5,128,150; 5,186,945; 5,360,605; 5,370,869; 5,589,072; and 5,609,864 by the present inventor. The contents of these patents are incorporated herein by reference.
Initially some workers objected to these iodine methods because they feared excessive amounts of free (elemental) iodine or combined iodine would be left in the disinfected product. However, the present inventor was able to demonstrate that chromatographic "capture" techniques could overcome these objections. By capture is meant the use of a resin or other material that binds iodine so strongly as to effectively remove all free iodine from a solution flowing through the capture material. Of course, a capture material that binds free or elemental iodine cannot remove covalently bound iodine. However, experimentation has shown that the organic reactions by which iodine becomes covalently bound are relatively slow. If a protein solution is rapidly iodinated by contact with an iodine source and then immediately passed through an effective capture agent, the amount of covalently bound iodine is negligible.
Thus, the major problem with the iodine system is not the presence of iodine in the final product. Rather, the interaction of the proteins with iodine may result in permanent alteration of the protein even though little or no iodine remains bound. This denaturation is, perhaps, most obvious as loss of enzymatic activities. The complex system by which human plasma forms a clot is especially liable to such damage. Also subtle damage can be apparent in the loss of growth factors as when an iodine-treated material is less effective at supporting cell growth in tissue culture.